The two halves fit together tightly, although there is good clearance and airflow around everything. Without ductwork, I wouldn't want to restrict airflow any more than it is already.

The additional USB and Firewire ports mounted as they are on the outer edge of the case is another improvised design element. I was lucky in that they just barely fit. However, I am limited to hard disks that have an open sunken front. Some hard disks are squared off at the front end. These would not fit.

There are three polycarbonate panels comprising the front. One on the bottom supports the I/O plugs as the screws run through counterbored holes. The next panel is cosmetic to make the front flush with the rest of the case. And the last, uppermost panel, guards the master power switch and the two snap switches that are for power and reset. These are all held together with two machine screws and four rubber washers. Again, this was an improvised solution. I originally wanted to have switches completely recessed into the aluminum, obviating the need for a front panel of this complexity.

The final product isn't perfect. But it's the first computer I've built and the third project with machine tools. After I had finished the aluminum frame and had the computer booting and running, for a short while I considered making the outer covering panels of heavy cardboard. I was so tired. I'm glad that I stuck it out and used polycarbonate. The fit of the panels is tight. The top, bottom, and rear panels are held in by friction only. The front and side panels are held in by screws. Note there are two large holes in the top for exhausting warm air. The five holes in the side are for intake using the power supply fan. So the case operates under positive pressure, the opposite of usual, again suited to Borg technology.

Conclusion

If I could do it over, I'm not sure I would! An off-the-shelf solution is very functional and much cheaper. There are attractive commercial alternatives. The Borg Appliance is heavily overengineered mechanically yet not really strong enough to be considered ruggedized in my view. There is a lot of merit in conventional sheet metal construction. But if coolness weren't important, probably all desktop computers would be generic beige PC clones.